Web application security testing is a process that seeks to find vulnerabilities in websites. It involves a series of steps aimed at gathering information about the target system, finding faults or vulnerabilities and researching for exploits that can successfully compromise the web application.

Web applications are a growing part of every business and can hold sensitive data that is accessed by third parties. So, it is vital to keep these applications safe at all times.

Cross-Site Scripting

Cross-Site Scripting (XSS) is a type of security vulnerability that affects web applications. It occurs when a web application receives user input and incorporates it unsafely within the output it generates. This output can be sent directly to the victim’s browser or displayed as part of a web page that a victim loads.

XSS vulnerabilities are one of the most prevalent and dangerous types of web application flaws. They can allow an attacker to gain unauthorized access to sensitive information such as cookies and session tokens, and rewrite HTML content without the user’s knowledge.

Most XSS attacks involve the execution of malicious JavaScript code on an end user’s device. This code can be injected into any website or web application that accepts user-input. This can include search engines, login forms, message boards, comment boxes, and other functions that are used by users to communicate with the web application.

These attacks typically exploit flaws in web application validation, which allows an attacker to inject a string of arbitrary code into the output. It’s important to test for XSS vulnerabilities in both automated and manual testing processes.

Stored XSS, also known as persistent XSS, is the most damaging kind of XSS attack. This kind of attack is often used to compromise a web application and steal user credentials or to implant a backdoor for further attacks. It typically occurs when a cybercriminal injects a malicious JavaScript payload into a database, blog, forum, or comment field that’s visible to the victim.

Reflected XSS, or non-persistent XSS, is the most basic form of XSS, in which a web application responds to an HTTP request with unaltered user input and then reflects that input back as a response to the victim’s browser. This type of XSS is commonly found on search results and error message sites, and can be used to redirect or manipulate traffic.

This kind of XSS can be easily avoided by performing appropriate validation and escaping for user-input data. This process can be done by manually submitting input to the application and then using a tool like an XSS scanner or a test framework that performs a thorough analysis of each HTTP response.

SQL Injection

Web applications often use SQL databases to store sensitive information, such as user names and passwords. A malicious user may exploit a SQL Injection vulnerability to gain access to these data and steal customer information, trade secrets, and intellectual property.

A website is vulnerable to SQL Injection if any input field is not protected from this type of attack. For instance, when a user enters login and password information in the login form or a search field, it goes directly to the database without any protection. The attacker can then use this information to execute malicious commands and frame SQL statements to the database.

There are several techniques that can be used to prevent these vulnerabilities. Some of them include encoding inputs, using prepared statements, parameterized queries, and object-relational mapping frameworks.

During testing, it is important to make sure that all fields are protected from this attack. For example, the search bar on the home page of an online shopping application would ask for products such as apples, oranges, milk, and chocolate. If any of these fields are not protected against SQL Injection, then the attacker can obtain the names and descriptions of all products.

In this case, it is also possible to test if an input field is vulnerable by sending a specific SQL query to the web application. The attacker can then see whether the database responds instantly or after a certain amount of time. The result can be used to determine if the query is true or false, which can help the attacker get the information that they need.

This technique is useful for time-based injection. In this technique, the attacker sends a SQL query to the database and makes it wait for a specified number of seconds before responding. If the response takes longer than that, then the query is likely to be false.

The results of this query are then returned to the application’s responses, allowing the attacker to retrieve all usernames and passwords. This can be useful in determining whether or not the application’s authentication mechanisms are vulnerable. It can also be used to extract information about the database’s version and structure.

Password Cracking

Password cracking is the process of figuring out passwords from encrypted data. It can be used as a way to help users recover passwords or as a way to gain unauthorized access to systems and resources.

The first step to preventing password-cracking is creating strong, unique passwords that are hard to guess. This requires a combination of security best practices and strong user-account management.

Another way to increase the strength of your passwords is to use a different password for each account. This practice will help to mitigate the risk of a broad range of password re-use strategies, including brute force and dictionary attacks.

In addition to using strong, unique passwords for your accounts, you should also ensure that the passwords are not shared among users. This is especially important for privileged accounts that require a high level of access to the system.

Several techniques can be used to try to crack passwords, such as brute force, dictionaries, and rainbow tables. Each technique has its own specific methods to attempt to figure out a password and encrypt it with a hash function.

The hash function essentially takes the arbitrary-length input and produces an encrypted version of it that is virtually impossible to decipher. For this reason, it is necessary to store passwords in encrypted form before storing them in a database.

A password is generally stored in a text file with a cryptographic hash, which generates a series of numbers and letters that can be represented as a string. This string is then compared against the encrypted hash to see if it matches.

In some cases, a simple brute force attack is sufficient to figure out a password, but in other cases, the attacker needs a more sophisticated approach. This requires a more powerful computer with the ability to run multiple hash functions at once.

This method of password recovery can be difficult to implement in a single application, but it can reduce the time it takes for an attacker to crack passwords. This method is also a good way to assess the overall strength of the passwords for your website or application, and make adjustments as needed.

Authentication

Authentication is the process of verifying that a user is who they claim to be before they gain access to a resource. This can be done by comparing a user's credentials (such as passwords) with a database of authorized users. If a user's credentials match those stored in the database, they are granted access to the resource.

Typical authentication factors include username-and-password combinations, PIN codes, security questions, and other forms of verification. Behavioral biometrics such as retina scans, voice recognition, and fingerprints are also used to verify user identity.

The way that a user is authenticated can vary depending on the type of system they use. Some systems require only one authentication factor, while others require two or more.

Some examples of strong authentication are single sign-on (SSO) services that authenticate users once and then pass this information on to every application, or certificate authentication, where a user's ID/Password is encrypted by the organization's certificate.

Another important part of a user's authentication is authorization, which is the ability to determine what they can and cannot do with a resource. This allows a person to use the resource only as authorized and prevents privilege escalation, an attack where a user gains access to an application, then changes their privileges or role to expand their access.

Authorization is often performed before authentication, and it can be a good idea to execute both security methods together. Performing both processes ensures that the user's identity and permissions are verified and that they cannot alter them to gain access to sensitive data.

Authentication and authorization are both essential to web application security testing, since they allow the security solution to identify the user performing an action request and establish their identity. Without this functionality, the solution may not be able to log or audit user activity and will have difficulty detecting and preventing security issues and attacks from occurring in the future.

Authentication can be difficult to test, but it is necessary for a security solution to be able to identify users and their activities. It also can help prevent unauthorized access to applications, and it can help protect against other security vulnerabilities such as SQL injection.